What do I have? (What version of Dashboard?)

I have a drobo product I purchased several years ago (long since out of warranty) the model is listed as DRO40-U. What is that? Gen 1, 2, 3? Something else?

Trying to figure out what version of Drobo Dashboard to use…

4-bay with one USB port (Gen1)

4-bay with one USB and 2 Firewire (Gen2)

4-bay with one USB3 (Gen3)